1. Field of the Invention
The present invention relates to a chromatographic analyzer such as a gas chromatograph (GC), a liquid chromatograph (LC), or a chromatograph mass spectrometer (GC/MS or LC/MS) obtained by combination of such the chromatograph with a mass spectrometer (MS).
2. Description of the Related Art
In a chromatographic analysis using a separation column, an analysis condition according to characteristics of the column is set prior to the analysis of an intended specimen, and the analysis is automatically performed according to the analysis condition. In general, a standard specimen containing a compound to be analyzed is actually analyzed, and an optimum analysis condition is set on the basis of the analysis result. Hereinafter, a gas chromatograph mass spectrometer (GC/MS) obtained by combination of the gas chromatograph (GC) with the mass spectrometer (MS) will be described as an example.
As a data collecting method in the MS section of the GC/MS, there have been known a so-called scanning measurement and a selected ion monitoring (SIM) measurement, and any one of those measurements is selected as usual (for example, refer to JP 10-283982 A). In the scanning measurement, since the repetitive mass number is scanned within a given mass number range, all of ions that are contained within the mass number range are detected. Therefore, the scanning measurement is useful for a case in which the mass number of a component to be analyzed is unknown, including the qualitative analysis of an unknown specimen. On the other hand, in the SIM measurement, only ions having one or more specific mass numbers designated in advance are selectively detected in a time division fashion. Therefore, the SIM measurement is useful for a case in which a material to be analyzed is known, and the quantitative analysis of the material is conducted with a high sensitivity.
As the data collection conditions (i.e., scanning measurement parameters) in a case of conducting the scanning measurement, it is necessary to set a measurement start time and a measurement end time together with the mass number range to be measured. For example, in a case where the mass number range is set to 100 to 500, the measurement start time is set to 5 minutes, and the measurement end time is set to 18 minutes, a time point at which the specimen is injected into a specimen gasifying chamber that is provided at a column inlet is set as zero, the mass number range of 100 to 500 is repeated with a given mass number step width, and the detected data is collected while performing mass scanning for 13 minutes, from a time point at which 5 minutes elapse to a time point at which 18 minutes elapse.
On the other hand, as the data collection conditions (i.e., SIM measurement parameter) in a case of conducting the SIM measurement, it is necessary to set one or more mass numbers to be measured as well as the measurement start time and the measurement end time. However, in general, the different mass numbers are measured according to the eluting times of various components from the column, so a plurality of measurement time ranges that are regulated by the measurement start time and the measurement end time can be set. For example,
The measurement time range: 5 to 8 minutes, the measurement mass number: 151, 120, and 130.
The measurement time range: 8 to 10 minutes, the measurement mass number: 250, 273, 157, 311, 256, and 450.
The measurement time range: 10 to 12 minutes, the measurement mass number: 167, 345, and 327.
Thus, the measurement time range is sectioned, and one or more measurement mass numbers are set for each of the measurement time ranges. At the time of executing the analysis, in the MS section, the detected data is collected while sequentially switching over the mass number to be measured with a time elapse from the specimen injection time point according to the setting contents. In this specification, one measurement time range of the SIM measurement is called “ion set”. That is, in the above example, three ion sets are set.
Incidentally, in the gas chromatograph, a time when the peak of the same component appears on the chromatogram is varied due to various factors. For example, the time is varied in a case of cutting an inlet portion of a capillary column by a given length in order to maintain the capillary column, in a case of changing a temperature rising program of a column oven that is one of the analysis conditions, or in a case where the column is exchanged to a column that is different in size such as the inner diameter or the length.
In the GC/MS, in a case where there is a factor that causes a variation of the chromatogram in the time axial direction, it is necessary to change the above data collection conditions that nave been set in advance (specifically, temporal parameter such as the above measurement time range). In the case of the scanning measurement, it is only necessary to change the two temporal parameters of the measurement start time and the measurement end time. However, in a case of the SIM measurement, all of the measurement start time and the measurement end time of the respective ion sets must be changed. In the existing GC/MS, the number of maximum ion sets that can be set is larger, specifically for example, 32, 64, or more, and in a case of setting a large number of ion sets, the change of the temporal parameter as described above is a significantly laborious work for an operator.
Also, in the GC/MS, there is a case in which a measurement that combines the scanning measurement with the SIM measurement, or the MS/MS (MSn) analysis is conducted. Even in this measurement, it is necessary to set various parameters every time the compound is eluted from the column, so when the chromatogram is varied in the time axial direction as described above, those parameters must be also changed. Also, the changing operation is significantly troublesome and laborious in a case where there are many compounds to be measured.
Further, there arises the same problem not in the GC/MS but in a case of executing a process that depends on the processing condition including the temporal parameter, for example, fractionating and sorting the specimen component that is temporally separated by the column as with the preparative liquid chromatograph. Even in this case, the changing operation of the processing conditions is troublesome, for example, when the number of specimen components to be fractionated and sorted is large.